Windows 7 Use second, external TFT through HDMI port to extend local desktop: second TFT becomes black

[pstein]

On my notebook (max screen resolution: 1920x1080) there is a HDMI port. I plugged in a HDMI cable from a second, external TFT screen (max resolution 1680x1050).

When I go now (under Win7) to

Control Panel/Appearance and personalization/Display/Screen Resolution

and select "Duplicate these displays" (under drop down Multiple displays") then
the notebook screen resolution is automatically switched to 1680x1050 and duplicated on the external screen.

Fine so far.

Now I select "Extend these displays" in order get a bigger desktop.
Unfortunately the second screen gets black now. The local desktop screen is NOT enlarged as desired.

Whats wrong?

Do I have to set other options additionally?

Do I have to install locally (on notebook) drivers for the second, external TFT as well?

Thank you
Peter

 

[Saltgrass]

Don't know if you have an Intel Graphics provider, but the link below might describe your problem. There are other FAQs on the site about different resolutions and such.

Also, do you know what type of HDMI cable you are using. There were some comments in the forums about needing different types of a cable to keep it from going black. It would seem a cable the came with the monitor would be able to support the resolution, but not really sure.

Graphics — Unable to use the native resolution